Her2 is expressed in ~25% of breast cancers and correlates with highly aggressive disease. Her2-targeted therapies are highly efficacious against Her2-positive cancer, yet no clinical imaging agents can assess Her2 status in vivo. EvoRx Technologies has developed a method to discover cyclic peptides that have antibody-like affinities and selectivities, high stability in serum, and rapid systemic clearance. In our Phase I contract, we showed that EVO- 004 has rapid, high levels of tumor uptake with minimal background in mouse models, developed an efficient, automated radiochemical synthesis, and obtained preliminary PET/CT images in mice showing specific tumor uptake as well as rapid clearance and low liver uptake. In Phase II, we aim to complete pre-clinical experiments, enabling first-in-human PET/CT imaging studies with EVO-004. We will use mouse model imaging studies of primary and metastatic cancer models to establish the sensitivity and limit of detection for Her2-positive disease, optimize EVO-004 radiochemical synthesis for clinical production, perform GMP validation studies, and establish dosimetry in rodent and primate models to determine tracer toxicity and establish the maximum safe dose for patient trials. Lastly, we will obtain an IND to deploy our PET tracer in patients with Her2-positive inflammatory breast cancer to demonstrate safety and concordance with biopsy-proven Her2-positive disease.